It is reasonable to predict on the basis of acoustic research on stops and fricatives in adults that comparable data for children would provide important information about their production strategies and acoustic correlates of sound features for speech perception. Although there are major anatomical and speech timing differences between adults and children, little data exist for children on acoustic properties of obstruents. It is important for theoretical and clinical reasons that acoustic data be obtained for children. Acoustic information on children's speech would provide a basis to evaluate from a developmental perspective such theoretical issues as acoustic invariance in stop production and perception, and models of segmental fundamental frequency (FO) effects. In regard to clinical issues in speech pathology, acoustic information on obstruents produced by normal children would provide a standard for the evaluation of the role of coarticulatory processes in disorders of speech production. The specific aims of this investigation are to obtain spectral and FO data on stop-vowel and fricative-vowel sequences for children between 8 and 9 years of age. Smoothed spectra will be calculated using a linear prediction algorithm, and FO will be measured using a computer waveform editing program. The long term objectives of this project are as follows: 1. To compare acoustic properties of obstruents of normal children to those of children with disorders of speech production; and 2. To identify acoustic correlates of stops and fricatives in children and then examine these cues in normal children and those with disorders of articulation through identification and discrimination perceptual tests.